A power control circuit and method of formation is provided, which in one embodiment includes a low voltage detection circuit to process a rectified input voltage from at least one alternating current (AC) voltage source and to output a low voltage indication signal upon detection of an initiation of an increase in the rectified input voltage; and a driver circuit configured to receive a signal representative of the low voltage indication signal and, in response, to output a drive signal to the switch control input of the power switch to turn on the power switch.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A power controller circuit configured to control a power switch that provides a regulated output and has a switch control input, comprising: a low voltage detection circuit to receive a combined rectified alternating current (AC) voltage provided by a first rectified AC input voltage combined with a second rectified AC input voltage; said low voltage detection circuit configured to output a low voltage indication signal upon detection of an initiation of an increase of the combined rectified AC voltage said low voltage synchronization circuit including a diode having a first port configured to receive the low voltage indication signal and a second port; a low voltage synchronization circuit configured to receive and condition the low voltage indication signal and to output a synchronization pulse; and a hysteretic regulator circuit configured to receive the synchronization pulse and, in response, to output a drive signal to the switch control input of the power switch to turn on the power switch, said hysteretic regulator circuit having a comparator circuit comprising: a first input configured to receive the synchronization pulse and coupled to said second port of said diode of said low voltage detection circuit; a second input coupled to a reference voltage source; and a first output configured to output the drive signal in response to receiving a voltage at said first input that satisfies a voltage threshold defined, at least in part, by the reference voltage.
2. A power controller circuit configured to control a power switch that provides a regulated output and has a switch control input, comprising: a low voltage detection circuit to receive a combined rectified alternating current (AC) voltage provided by a first rectified AC input voltage combined with a second rectified AC input voltage; said low voltage detection circuit configured to output a low voltage indication signal upon detection of an initiation of an increase of the combined rectified AC voltage; a low voltage synchronization circuit configured to receive and condition the low voltage indication signal and to output a synchronization pulse; a regulator circuit configured to output a drive signal to the switch control input of the power switch to turn on the power switch; and a discharge control circuit configured to receive the low voltage indication signal and, if the low voltage indication signal is not received for a predetermined time period, to output a discharge signal to cause the power switch to turn on to discharge a capacitor.
3. The power controller circuit according to claim 2 , wherein said hysteretic regulator circuit is configured to receive the discharge signal and, in response, to output the drive signal to turn on the power switch to discharge the capacitor.
4. The power controller circuit according to claim 2 , wherein the power switch comprises a transistor having first current carrying electrode configured to receive the combined rectified AC voltage.
5. The power controller circuit according to claim 2 , wherein said low voltage detection circuit comprises a comparator circuit configured to receive the combined rectified AC voltage and to detect the initiation of an increase in the combined rectified AC voltage.
6. A power controller circuit configured to control a power switch that provides a regulated output and has a switch control input, comprising: a low voltage detection circuit to process a rectified input voltage from at least one alternating current (AC) voltage source; said low voltage detection circuit configured to output a low voltage indication signal upon detection of an initiation of an increase in the rectified input voltage; a driver circuit configured to output a drive signal to the switch control input of the power switch to turn on the power switch; and a discharge control circuit configured to receive the low voltage indication signal and, if the low voltage indication signal is not received for a predetermined time period, to output a discharge signal to cause the power switch to turn on to discharge a capacitor.
7. The power controller circuit according to claim 6 , further comprising a low voltage synchronization circuit configured to receive and condition the low voltage indication signal and to output a conditioned low voltage indication signal as the signal representative of the low voltage indication signal to said driver circuit.
8. The power controller circuit according to claim 6 , wherein the rectified input voltage comprises a first rectified AC input voltage that is combined with a second rectified AC input voltage.
9. The power controller circuit according to claim 6 , wherein said low voltage detection circuit comprises a comparator circuit configured to receive the rectified AC voltage and to detect the initiation of an increase in the rectified AC voltage.
10. The power controller circuit according to claim 6 , wherein driver circuit comprises: a comparator circuit having a first input configured to receive the signal representative of the low voltage indication signal, a second input connected to a reference voltage source; and a first output configured to output the drive signal in response to receiving a voltage at said first input that satisfies a voltage threshold defined, at least in part, by the reference voltage.
11. The power controller circuit according to claim 10 , further comprising a diode having a first port configured to receive the low voltage indication signal and a second port connected to said first input of said comparator circuit.
12. The power controller circuit according to claim 10 , wherein said comparator circuit comprises a hysteretic comparator circuit.
13. The power controller circuit according to claim 6 , which is implemented as a semiconductor device that also includes the power switch.
14. A method of forming a semiconductor device for providing a regulated output, comprising: providing a low voltage detection circuit to receive a combined rectified alternating current (AC) voltage provided by a first rectified AC input voltage combined with a second rectified AC input voltage; providing a transistor having a control electrode, a first current carrying electrode configured to receive the combined rectified AC voltage, and a second current carrying electrode to be connected to a load; configuring the low voltage detection circuit to output a low voltage indication signal upon detection of an initiation of an increase in the combined rectified AC voltage; configuring a low voltage synchronization circuit to receive the low voltage indication signal and to output a synchronization pulse; configuring a regulator circuit to receive the synchronization pulse and, in response, to output a drive signal to the control electrode of the transistor switch to turn on the transistor; and a discharge control circuit to receive the low voltage indication signal and, if the low voltage indication signal is not received for a predetermined time period, to output a discharge signal to cause the transistor to turn on to discharge a capacitor.
15. The method according to claim 14 , further comprising: configuring a first input of the hysteretic regulator circuit to receive the synchronization pulse; and configuring the hysteretic regulator circuit to output the drive signal in response to receiving a voltage at the first input that satisfies a threshold voltage defined, at least in part, by a reference voltage.
16. The power controller circuit according to claim 15 , further comprising: configuring a first port of a diode forming at least part of the low voltage synchronization to receive the low voltage indication signal; and connecting a second port of the diode forming at least part of the low voltage synchronization to the first input of the hysteretic regulator circuit.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
May 10, 2012
October 14, 2014
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